AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Investigating Biomass Burning Contribution to Brown Carbon in Beijing
CAIQING YAN, Mei Zheng, Yury Desyaterik, Amy P. Sullivan, Jeffrey Collett, Peking University
Abstract Number: 390 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Biomass burning has been recognized as one of important sources of brown carbon, which plays an important role on regional air quality, radiative forcing and climate change. Agricultural residues and residential biofuel burning are two major types of biomass burning activities, which can contribute significantly to fine particulate matter (PM$_(2.5)) in some cities during episodic events in China. However, investigation of biomass burning contribution to brown carbon is very limited in Beijing, the capital city of China. This city has frequently experienced severe haze episodes during the last two years, especially during harvest and colder seasons. In this study, ambient PM$_(2.5) samples were collected at an urban site in summer and winter 2013 in Beijing. Light absorption properties of water extracts of these offline samples were measured. Carbohydrates (biomass burning markers) were analyzed using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). And high performance liquid chromatography equipped with a UV/Vis absorbance detector and a time-of-flight (ToF) mass spectrometer (LC/DAD-ESI-HRTOFMS) was applied to determine elemental compositions of light absorbing compounds, especially those from primary and secondary biomass burning sources. High levoglucosan concentrations have been found in some summer samples but it consistently remained a high level in almost all winter samples. Abundant nitrophenols and aromatic carbonyls have also been found in these offline samples especially during days under significant biomass burning influence. In addition, high-time resolution single particle aerosol mass spectrometry (SPAMS) will be used to identify the types (fresh or aged) of biomass burning aerosols. Contribution of primary and secondary biomass burning aerosols to brown carbon in Beijing will be further discussed based on their light-absorption properties, light-absorbing compounds, smoke markers, types of biomass burning aerosols, as well as types of biomass.
*Corresponding author: Mei Zheng, mzheng@pku.edu.cn